SUMMARY OF OBJECTIVES: 1. Evaluation of new renin-angiotensin inhibitors. 2. Characterization and modulation of the sequence of biochemical events during the angiotensin-receptor reaction leading to prostaglandin (PG) biosynthesis and AII tachphylaxis. 3. We are intensively studying the mechanism for supersensitive prostaglandin and thromboxane release by angiotensin in the hydronephrotic kidney.